It only became known to researchers through aerial imagery, which revealed the faint outline of a structure that time and grass have done their best to erase. That it escaped cartographic notice entirely is itself a small puzzle, given that enclosures of this kind were a common feature of the Irish countryside for centuries.

The site measures 24 metres across in both directions and is defined by a low stony bank, the remains of what may once have been a more substantial wall. Most of the circuit survives only as intermittent moss-covered hummocks with stones protruding at odd angles; a slightly more legible stretch appears at the north-east, where a sod-covered bank still stands between 0.2 and 0.6 metres in height depending on which side you measure from. At the centre of the interior, a shallow circular hollow roughly four metres in diameter and about 0.4 metres deep sits in the uneven, thistle-covered ground. A faint raised rim runs along its outer western edge. What this hollow represents is not known; it may be the ghost of a structure, a collapsed feature, or something else entirely. Modern field fences have since been driven across the enclosure, clipping both the hollow and the western edge, and a fragment of an older boulder-built fence abuts the south-west side before breaking off after five or six metres. The natural scarp on the southern edge and a river roughly 200 metres to the west suggest whoever built here chose the spot with some attention to the surrounding terrain.

What makes Ummeryroe particularly difficult to categorise is what it is not. Just 155 metres to the north-north-west lies a well-defined earthen rath, the kind of enclosed farmstead associated with early medieval Ireland, typically consisting of a circular bank and ditch surrounding a domestic space. The Ummeryroe enclosure is described as very different in form from that rath, which leaves its date, purpose, and origins genuinely open. It sits in the landscape as an unresolved question, part of a wider pattern of sites that resist easy classification and reward patient attention to the ground beneath your feet.